Backpack



FIG. 1 is a front perspective view of the backpack claimed herein;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines depict portions of the article and stitching and form no part of the claim. 

CLAIM The ornamental design for a backpack, as shown and described. 